1. Field of the Invention
The present invention relates to a tooth-hardening apparatus used by an infant for hardening his or her teeth.
2. Background Art
A several-month-old baby should gradually harden his or her teeth through training. Some tooth-hardening apparatuses have been conventionally used for such tooth-hardening training (see, for example, Japanese Patent Laid-Open Publication No. 2000-279487).
As described above, some tooth-hardening apparatuses have been conventionally developed. A period when an infant hardens his or her teeth partially overlaps a period when an infant continues to suck a nipple. Thus, if an infant can harden his or her teeth, while continuing a sucking motion, it is possible for the infant to smoothly shift to a tooth-hardening training, and this is advantageous for the infant.